Inside Jackson's home, Murray was making calls and texting the morning of June 25, 2009.
Paramedic Richard Senneff testified last week that he saw Murray making or receiving a phone call while in the ambulance with Michael Jackson's lifeless body. Prosecutors believe that call was to Alvarez.
Alvarez, 29, has a 2-year-old son with Murray, and the two were living together at her Santa Monica apartment in 2009. She said she was excited to know that Murray was Jackson's personal physician. She was able to meet Jackson a few times through Murray, and was planning to go with Murray on the "This Is It" tour.
Prosecutors believe Murray was star struck, and his status helped him get dates, despite the fact that he was married at the time. But the defense's position is that Murray was devoted to Jackson and proud of his role.
Alvarez testified that Murray would leave almost every night to treat the King of Pop, and he would not return until morning.
When prosecutor Deborah Brazil asked if she was aware of Murray's contract with Jackson for $150,000 a month, she said she didn't know, which contradicted her testimony at a preliminary hearing.
"You were under oath at the prior proceeding when you were answering Mr. Walgren's questions, you remember that, don't you?" Brazil asked.
Alvarez answered that she did.
"And you answered truthfully, and told Mr. Walgren that the contract had come through the fax machine, you were curious, and you looked at it, and that's how you knew some details about the contact. You would agree that you told the truth when you told Mr. Walgren that, didn't you Ms. Alvarez?" Brazil said.
Alvarez replied, "Absolutely, but as of this moment, I don't recall that specific moment. There's been a lot that has been going on over the past two years, and things do become very blurry."
During a sidebar at a preliminary hearing, Deputy District Attorney David Walgren described Alvarez as an uncooperative witness who has refused to cooperate with police.
Alvarez testified that she signed for several cartons of pharmaceuticals delivered to the apartment - six shipments in three months.
Then the owner of a Las Vegas pharmacy testified about the content: saline bags, multiple sedatives and propofol.
A woman who also had a relationship with Murray, Sade Anding, took the stand earlier. She was one of three people Murray called in the hour before he noticed Jackson had stopped breathing.
On Monday, testimony included Murray's phone records, and the most significant call was an 11-minute phone call at 11:51 a.m. to Anding. It was the closest time marker offered by the prosecution as to when Jackson may have died.
The Texas cocktail waitress said she went on talking, not realizing Murray had stopped listening.
"I said, 'Hello, hello,' and I didn't hear anything, and that's when I pressed the phone against my ear," Anding testified.
She heard mumbling and coughing, but she could not tell what was going on. Prosecutors believe Anding was talking with Murray when he realized Jackson wasn't breathing.
During cross examination, defense attorneys asked if she could tell if that mumbling was Murray, but she said she could not make out whose voices they were.
Anding told the court that Murray told her to contact his lawyer before talking to police.
The prosecution maintains that Jackson died of an overdose of propofol administered by Murray, while the defense contends that Jackson administered the drug to himself.ABC News learned that the pop star's fingerprints were not found on any propofol bottles in his bedroom. It remains to be seen if his prints were seen on a syringe.
The prosecution plans to play a roughly two-hour audio tape in court on Wednesday. It is the first detailed interview of Murray with LAPD detectives.Murray is on trial for involuntary manslaughter for Jackson's sudden death on June 25, 2009, at the age of 50. Prosecutors allege Murray tried to hide the fact that he had been giving propofol to Jackson.
Murray, 58, has pleaded not guilty and has denied any wrongdoing. If convicted, he could face up to four years in prison and lose his medical license.
The trial is expected to last five weeks, with Oct. 28 being the estimated last day.